1. Field of the Invention
The present invention relates to drainage device technology and more particularly, to a motor shield for the drainage device of a cooling or air-conditioning system, which provides an airflow guiding function.
2. Description of the Related Art
A drainage device for use in a cooling or air-conditioning system generally uses a motor to provide a dynamic force for drainage of water. However, a motor releases waste heat during operation. Therefore, a drainage device of this type must have a heat dissipation device to assure normal working of the product.
Taiwan Utility Model M308567, issued to the present inventor, discloses a heat dissipation technique entitled “Motor shield with hot airflow guiding function to dissipate heat”. According to this design, an arched guide board is arranged on the surface of the top side of the motor shield for shunting discharged gas so that a part of the discharged gas, subject to the guidance of the arched guide board, is kept flowing within a predetermined distance without scattering, enhancing the stability of the eddy flow of the discharged gas.
However, the aforesaid prior art technique is adapted for guiding the discharged gas that flows out of the motor shield but not for guiding the flow of gas inside the motor shield. According to this design, the heat dissipation effect produced subject to the airflow guiding functioning of the arched guide board is limited.
U.S. Pat. No. 7,252,482, entitled “Motor driven pump with improved motor cooling air flow”, discloses an electric motor-driven pump adapted for pumping condensate from refrigeration and air conditioning systems in which a motor cover mounted on a reservoir cover defines a vertically extending cooling air inlet and horizontally extending discharge ports for the flow of cooling air propelled by a fan. This design does not provide a significant airflow guiding function. The horizontally extending discharge ports simply facilitate outward dispersion of cooling air propelled by the fan. This arrangement does not significantly enhance heat dissipation.